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- In 1989, NASA and a landscaping trade group studied a dozen plants and their ability to reduce toxins from the air of a sealed chamber.
- Researchers did not study what would happen if humans were in sealed chambers, or whether the plants would produce enough oxygen to sustain human life.
Could a common houseplant keep you alive in a sealed room if you couldn’t open the windows?
A Facebook post claims that the snake plant can.
"According to NASA's Clean Air Study, the snake plant is so effective in producing oxygen that if you were locked in a sealed room with no airflow, you would be able to survive with just 6-8 plants in it. NASA recommends 15 to 18 medium to large size plants for 1,800-square-foot home for optimum air quality."
The post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)
NASA did conduct a study, in partnership with a landscaping trade association, of how plants can solve indoor air pollution. But its study didn’t draw conclusions about whether plants could produce enough oxygen to keep people alive in a sealed room. Other research has dismissed the idea of air-cleaning plants as impractical.
The study covered two years of data and was published in 1989. It was supported by a division of the NASA Office of Commercial Programs and the Associated Landscape Contractors of America. The landscaping group then used the study’s findings to promote the use of plants indoors.
Study authors looked at a dozen plants, and how they reduce the presence of several toxins: benzene, trichloroethylene and formaldehyde. One of those plants was Sansevieria laurentii, also known as a snake plant or mother-in-law’s tongue.
The plants were placed in sealed Plexiglas chambers, which were contaminated by the toxins. Two chambers were 30-by-30-by-30-inch cubes, and two were twice the volume. Air samples were taken in timed intervals after the toxins were introduced.
The snake plant was shown to remove TCE, benzene and formaldehyde, though other plant varieties removed more of these toxins, according to the study. Researchers wrote that the plants, along with activated carbon filters, "have demonstrated the potential for improving indoor air quality by removing trace organic pollutants from the air in energy-efficient buildings." They said that fans that move air through activated carbon filters should be included in any plan to reduce indoor air pollution with plants.
But the Facebook claim is about what would happen if a human was locked in a room with no airflow. The NASA study did not test how the introduction of humans into the chamber would change the results, and researchers acknowledged this. They wrote that scientists were looking into it, but as of the study’s publication in 1989, they said, research was limited: "NASA studies at Stennis Space Center, private studies by Biosphere 2 in Arizona, and USSR studies in Siberia are beginning to present a clearer picture of what man can expect to experience when sealed inside facilities with plants and soil as his major means of life support."
We reached out to NASA several times about this claim. A spokesperson directed us to the clean air study, but attempts to obtain more information about it were unsuccessful.
Since the NASA study, other scientists have looked into the effects of plants on indoor air pollution.
In 1992, an official with the Indoor Air Division of the U.S. Environmental Protection Agency, wrote a critique of the NASA study, and said that scaling up the number of plants used in the study for use in a house — the author estimates 680 plants would be required in a typical house — makes using them impractical, and would cause other problems, such as increased humidity.
A study published by the American Society of Horticulture Science in 2009 found that snake plants were effective at reducing ozone in indoor environments, but that more study would be necessary to determine the number of plants required in an area. The study recommended inexpensive houseplants as a way to mitigate indoor air pollution in the developing world.
In 2019, a review of a dozen studies over 30 years was published by scientists at Drexel University, and their findings show that plants are not effective at cleaning the air.
"Plants are great, but they don't actually clean indoor air quickly enough to have an effect on the air quality of your home or office environment," said Michael Waring, an associate professor of architectural and environmental engineering at Drexel.
Drexel researchers found that the natural air exchange that happens in buildings works faster than plants to remove volatile organic compounds. They also found that the number of plants required to remove such compounds makes it impractical to use them for this purpose. According to their calculations, it would take between 10 and 1,000 plants per square meter of floor space to compete with the air cleaning capacity of a few open windows or a building's air handling system.
A Facebook post claims that according to a NASA study, six to eight snake plants could produce enough oxygen to keep humans alive in a room with no airflow.
We found no evidence to support that claim. A 1989 NASA study found that snake plants could remove certain toxins from small sealed spaces under certain conditions. But it did not examine whether snake plants would be able to keep humans alive in sealed rooms. Other researchers have questioned the NASA study’s findings and found that relying on plants is an impractical way of cleaning indoor air.
We rate this claim False.
Facebook post, Dec. 10, 2021. Accessed Dec. 16, 2021.
Email interview, Rob Margetta, public affairs officer, NASA Headquarters, Dec. 16, 2021.
NASA Office of Commercial Programs – Technology Utilization Division, Associated Landscape Contractors of America, "Interior Landscape Plants for Indoor Air Pollution Abatement," B.C. Wolverton, Ph.D., et. al., Sept. 15, 1989. Accessed Dec. 21, 2021.
Alaska Master Gardener Blog, "Indoor air quality and plants - clear as smoke?" June 24, 2015. Accessed Dec. 21, 2021.
HortTechnology, American Society of Horticulture Science, "Effectiveness of Houseplants in Reducing the Indoor Air Pollutant Ozone," Heather L. Papinchak, E. Jay Holcomb, Teodora Orendovici Best, and Dennis R. Decoteau, January 2009. Accessed Dec. 21, 2021.
L.A. Times, "Indoor Air-Cleaning System Rooted in Plants," Jan. 13, 1991. Accessed Dec. 22, 2021.
U.S. Environmental Protection Agency, "Comment on the Use of Plants as a Means to Control Indoor Air Pollution," John R. Girman, branch chief, analysis branch, Indoor Air Division, 1992. Accessed Dec. 22, 2021.
Journal of Exposure Science & Environmental Epidemiology, "Potted plants do not improve indoor air quality: a review and analysis of reported VOC removal efficiencies," Bryan E. Cummings, Michael S. Waring, Nov. 6, 2019. Accessed Dec. 22, 2021.
Drexel University, news release, "Study: Actually, potted plants don't improve indoor air quality," Nov. 6, 2019. Accessed Dec. 22, 2021.
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